| Contraceptive efficacy of emergency contraception with levonorgestrel given before or after ovulation. | |
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MedLine Citation:
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PMID: 20399948 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: We aimed to evaluate whether emergency contraception with levonorgestrel (LNG-EC) administered after ovulation is equally effective to LNG-EC administered before ovulation. STUDY DESIGN: We studied a cohort of women attending a family planning clinic for EC. From interview, we recorded menstrual history, time of intercourse and of intake of LNG-EC. On the day of intake of LNG-EC and during 5 days' follow-up, blood samples were taken for examination of luteinizing hormone, estradiol and progesterone concentrations, and vaginal ultrasound examinations were done for size of the leading follicle and/or corpus luteum. Thereafter women were not contacted until next menses or pregnancy occurred. RESULTS: Of 388 women attending for LNG-EC, 122 women had intercourse on fertile cycle days according to ultrasound and endocrine findings. At the time of LNG-EC intake, 87 women were in Days -5 to -1 and 35 women were in Day 0 (day of ovulation) or beyond. With the use of the probability of clinical pregnancy reported by Wilcox et al. [N Engl J Med 333 (1995) 1517-1521], expected numbers of pregnancies among the 87 and 35 women were 13 and 7, respectively, while 0 and 6 pregnancies, respectively, occurred. CONCLUSION: We conclude that LNG-EC prevents pregnancy only when taken before fertilization of the ovum has occurred. |
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Authors:
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Gabriela Noé; Horacio B Croxatto; Ana María Salvatierra; Verónica Reyes; Claudio Villarroel; Carla Muñoz; Gabriela Morales; Anita Retamales |
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Publication Detail:
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Type: Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't Date: 2010-01-27 |
Journal Detail:
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Title: Contraception Volume: 81 ISSN: 1879-0518 ISO Abbreviation: Contraception Publication Date: 2010 May |
Date Detail:
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Created Date: 2010-04-19 Completed Date: 2010-07-29 Revised Date: 2011-02-04 |
Medline Journal Info:
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Nlm Unique ID: 0234361 Medline TA: Contraception Country: United States |
Other Details:
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Languages: eng Pagination: 414-20 Citation Subset: IM |
Affiliation:
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Instituto Chileno de Medicina Reproductiva (ICMER), Santiago, Chile. gnoe@icmer.org |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adolescent Adult Coitus Contraception, Postcoital* Contraceptive Agents, Female / administration & dosage* Female Humans Levonorgestrel / administration & dosage* Menstrual Cycle* Ovulation* Prospective Studies Young Adult |
| Chemical | |
Reg. No./Substance:
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0/Contraceptive Agents, Female; 797-63-7/Levonorgestrel |
| Comments/Corrections | |
Comment In:
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Contraception. 2011 Feb;83(2):187; author reply 187-8
[PMID:
21237347
]
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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